How do I test DNS lookup latency with... ns_bench?

Occasionally DNS name servers can have lookup delays for commonly accessed (cached) addresses. Of course, if a sluggish name server has a cache miss and has to check for a name at the root server, then the lookup delay will be even longer. Because the lookup delay for common addresses consists of two parts: the RTT time, the latency to the server, and the query time from the nameserver's cache, a simple pinging of the slow name server will not always show a problem if the server is sluggishly serving up the IP addresses to your browser.

Even worse than a simple delay, is a lookup query timeout when the name server fails to respond within a second or two or ever. Various OSes handle this differently, but WinXP will retry the lookup after one second and then begin trying additional nameservers with increasingly longer wait times. These timeouts can be a result of UDP packet loss en route to the nameserver and so are not always due to problems at the nameserver, but with the routers before it.

Feel like such a noob. I unzipped the files under my documents. Ran cmd. Put this in cd \My Documents\ns_bench\win32 and I get this error like it states.

If you see the "'ns_bench.exe' is not recognized as an internal or external command, operable program or batch file" error, then you are not running it from the directory (folder) that the ns_bench program is in.

Download the ns_bench zipped file to a folder, such as My Documents, and unzip it. It will make an ns_bench\win32 sub-folder containing its executable program, ns_bench, and the cygwin1.dll file. The program and its components are self-contained within the sub-folder and do not install to or affect your registry.

This is a command line tool, and once it is unzipped, you can run it by right clicking on the ns_bench\win32 folder, and selecting "Open Command Window Here" from the list if you have that particular Microsoft power toy installed (or see instruction 4a on the dig for Windows page for how to install "CMD Prompt Here" to your right-click menu),

... or

Click Start, then select Run, enter 'cmd" (or 'command" for Win98/ME) in the entry box, and hit the ENTER key. Then change the directory to where you unzipped it, e.g., if you downloaded to My Documents, enter 'cd \My Documents\ns_bench\win32' at the command line and hit the ENTER key.

If you see the "'ns_bench.exe' is not recognized as an internal or external command, operable program or batch file" error, then you are not running it from the directory (folder) that the ns_bench program is in.